Microbes encapsulated within crosslinkable polymers

Abstract

The invention relates to porous films comprising crosslinked electrospun hydrogel fibers. Viable microbes are encapsulated within the crosslinked electrospun hydrogel fibers. The crosslinked electrospun hydrogel fibers are water insoluble and permeable. The invention also relates to methods of making and using such porous films.

1. A porous film comprising crosslinked electrospun hydrogel fibers, wherein microbes are encapsulated within the crosslinked electrospun hydrogel fibers, and wherein the crosslinked electrospun hydrogel fibers are water insoluble and permeable, and contain viable microbes encapsulated within the fiber. 
     
     
       2. The porous film of  claim 1  wherein the film has an open pore structure. 
     
     
       3. The porous film of  claim 1  wherein the crosslinked electrospun hydrogel fibers comprise polyethers. 
     
     
       4. The porous film of  claim 3  wherein the polyethers comprise polyethylene oxide, polypropylene oxide, mixtures thereof, or co-polymers thereof. 
     
     
       5. The porous film of  claim 4  wherein the copolymer is a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide. 
     
     
       6. The porous film of  claim 5  wherein the polyethers comprise a mixture of the triblock copolymer and polyethylene oxide. 
     
     
       7. The porous film of  claim 3 , wherein the polyethers are functionalized with terminal acrylate or methacrylate groups. 
     
     
       8. The porous film of  claim 1  wherein the crosslinked electrospun hydrogel fibers comprise a mixture of PEO 99 -PPO 67 -PEO 99  DMA and polyethylene oxide. 
     
     
       9. The porous film of  claim 1  wherein the crosslinked electrospun hydrogel fibers comprise glycosaminoglycans. 
     
     
       10. The porous film of  claim 9  wherein the glycosaminoglycans comprise functionalized hyaluronic acid. 
     
     
       11. The porous film of  claim 1  wherein the crosslinked electrospun hydrogel fibers comprise proteins. 
     
     
       12. The porous film of  claim 1  wherein the microbes are capable of bioremediation. 
     
     
       13. The porous film of  claim 12  wherein the microbes are  Pseudomonas  sp. 
     
     
       14. The porous film of  claim 1  wherein the microbes produce ethanol. 
     
     
       15. The porous film of  claim 14  wherein the microbes are  Zymomonas  sp. 
     
     
       16. The porous film of  claim 1  wherein the microbes maintain viability for at least about one week at 4° C. 
     
     
       17. The porous film of  claim 1 , wherein the crosslinked electrospun hydrogel fibers have diameters in the range of about 0.6 microns to about 5 microns. 
     
     
       18. The porous film of  claim 1 , wherein the porous film has a thickness in the range of about 1 micron to about 10 cm. 
     
     
       19. The porous film of  claim 18 , wherein the porous film has a thickness in the range of about 10 to about 5000 microns. 
     
     
       20. A method of encapsulating microbes within crosslinked electrospun hydrogel fibers, the method comprising:
 (a) providing a mixture of microbes and a polymer, wherein the polymer is water soluble, is crosslinkable, and is capable of forming a hydrogel upon being crosslinked; 
 (b) electrospinning the polymer to form electrospun fibers, wherein microbes are encapsulated within the electrospun fibers; and 
 (c) crosslinking the electrospun fibers to form crosslinked electrospun hydrogel fibers, 
 wherein the crosslinked electrospun hydrogel fibers are water insoluble; and 
 wherein viable microbes are encapsulated within the fiber of the crosslinked electrospun hydrogel fibers. 
 
     
     
       21. The method of  claim 20  wherein the electrospun hydrogel fibers are crosslinked by contacting the electrospun hydrogel fibers with a crosslinking agent in a liquid polyol. 
     
     
       22. The method of  claim 21  wherein the liquid polyol is glycerol. 
     
     
       23. The method of  claim 21  wherein the liquid polyol is a sugar alcohol. 
     
     
       24. The method of  claim 23  wherein the sugar alcohol is xylitol, mannitol or lactitol. 
     
     
       25. The method of  claim 21  wherein up to about 70% of the liquid polyol is replaced with water. 
     
     
       26. The method of  claim 21  wherein up to about 50% of the liquid polyol is replaced with water. 
     
     
       27. The method of  claim 21  wherein up to about 30% of the liquid polyol is replaced with water. 
     
     
       28. The method of  claim 20  wherein the electrospun hydrogel fibers are crosslinked by contacting the electrospun hydrogel fibers with redox system that produces a free radical inhibitor in a solvent that comprises a liquid polyol and optionally water. 
     
     
       29. The method of  claim 28  wherein the redox system comprises at least a persulfate salt. 
     
     
       30. The method of  claim 29  wherein the persulfate salt is ammonium persulfate. 
     
     
       31. The method of  claim 28  wherein the redox system comprises ammonium persulfate, ferrous sulfate and ascorbic acid. 
     
     
       32. A method of crosslinking electrospun fibers in which microbes are encapsulated, the method comprising crosslinking in a liquid polyol; wherein, after crosslinking, (i) the electrospun fibers form crosslinked electrospun hydrogel fibers that are insoluble and permeable, and (ii) wherein viable microbes are encapsulated within the fiber of the crosslinked electrospun hydrogel fibers. 
     
     
       33. The method of  claim 32  wherein the act of crosslinking comprises treating the electrospun fibers with ammonium persulfate, ferrous sulfate and ascorbic acid. 
     
     
       34. The method of  claim 32  wherein the liquid polyol is glycerol. 
     
     
       35. The method of  claim 32  wherein up to about 70% of the liquid polyol is replaced with water. 
     
     
       36. A biosensor comprising microbes encapsulated within crosslinked electrospun hydrogel fibers, wherein the microbes are viable and capable of generating a signal in response to a chemical compound; and wherein the crosslinked electrospun hydrogel fibers are water insoluble and permeable, and contain viable microbes encapsulated within the fiber of the crosslinked electrospun hydrogel fibers. 
     
     
       37. The biosensor of  claim 36  wherein the signal is an electric signal. 
     
     
       38. An electrode comprising crosslinked electrospun hydrogel fibers, wherein microbes are encapsulated within, and wherein the crosslinked electrospun hydrogel fibers, are water insoluble and permeable, and contain viable microbes encapsulated within the fiber of the crosslinked electrospun hydrogel fibers, and are capable of electron generation or utilization. 
     
     
       39. The porous film of  claim 1  wherein the porous film is used in a bio-film reactor and wherein the encapsulated microbes are further capable of producing metabolites.